1. Field of Invention
The present invention relates to an electrooptical substrate device for an electrooptical apparatus, such as a liquid-crystal apparatus, of a so-called TFT active-matrix drive scheme for active-matrix-driving pixel electrodes by thin film transistors (hereinafter “TFTs”). The invention also relates to a manufacturing method for the same, an electrooptical apparatus including such an electrooptical substrate device, an electronic apparatus having such an electrooptical apparatus, and a manufacturing method for a substrate device.
2. Description of Related Art
In this type of an electrooptical substrate device, pixel-electrode-switching TFTs are respectively provided on a plurality of pixel electrodes that are arranged in a matrix form. Each TFT is turned on each time a scanning signal is applied to the gate electrode thereof, to write an image signal onto the pixel electrode through the TFT.
Particularly, N-channel TFTs, having as carriers high-mobility electrons, are used to enable control by the TFTs having a high-performance transistor characteristic when effecting pixel-switching control. Recently, as the drive frequency of an electrooptical apparatus increases, the N-channel TFTs having high-mobility electrons as carriers are still being used in order to cope with the higher driving frequency.
On the other hand, in order to perform a higher level of driving, such as high-frequency driving, there is a need to further enhance the performance of such a pixel-switching TFT. For this reason, it is proposed to apply the SOI (Silicon On Insulator) structure, or SOI art, in the semiconductor manufacturing technology to an electrooptical substrate device of that kind. Specifically, a single-crystal semiconductor layer is formed by bonding or the like on an insulating layer of quartz or sapphire formed on a substrate, to fabricate transistors on the single-crystal semiconductor layer. The application of such an SOI art makes it possible to fabricate single-crystal silicon TFTs that are higher in performance than the amorphous-silicon or polysilicon TFTs on an electrooptical substrate device.